The present invention relates to a head suspension to support a head slider in a disk drive apparatus, and more particularly, to a head suspension which is more stable during high speed acceleration and generates less dust.
FIG. 1 illustrates a structure of a head suspension of the related art. A load beam (spring arm) 1 made of stainless steel is spot-welded to a spacer 4 and the load beam 1 is fixed by a caulking method to an arm (not illustrated). Both sides of the load beam 1 are bent to form a rigid rib 1a. At the end portion of the load beam 1, a gimbal 2 made of stainless steel is spot-welded.
The end portion of gimbal 2 is bent toward the disk 14 to form a tongue portion 2a. The tongue portion 2a generates a spring force in the direction perpendicular to the surface of a disk 14.
At the surface of tongue portion 2a opposing the disk 14, a head slider 3 is mounted. The head slider 3 is generally fixed to the tongue portion 2a by a bonding method. A part of the surface opposed to the tongue portion 2a of the gimbal 2 is projected toward the tongue portion 2a to form a pivot 5.
The pivot can be formed by punching the gimbal 2 with a punch. The end portion of the pivot 5 is in contact with the inside surface opposite the surface to which the head slider 3 is mounted. When the disk 14 rotates, the slider 3 receives the air flow generated between the slider 3 and the disk 14. As a result, the slider 3 floats from the surface of disk 14, keeping a small gap, and rotates in every direction with the end point of pivot 5 used as a fulcrum.
The head suspension moves, on the occasion of reading or writing information from or to the disk, on the surface of the disk at a high speed so that the head slider can access the predetermined position on the disk. In recent years, with higher speed access, some disk apparatus drive the head suspension with an acceleration of 200 G or more.
In the head suspension of the related art, improvement in the access rate allows the tongue portion of the gimbal to slide, resulting in a drop of resonance frequency, which is the important characteristic of the head suspension, and a drop of positioning accuracy of the head. Moreover, friction between the pivot and tongue portion has resulted in the phenomenon that both elements generate dust within the disk enclosure as they wear out. If dust is adhered to the disk medium, it will cause a head crash or the like and thereby reliability of the disk apparatus is deteriorated.
As explained above, in the head suspension of the related art, there is a need for further improved high speed operation for disk apparatus, and higher reliability.
It is therefore a first object of the present invention to provide a new head suspension capable of high speed access.
A second object of the present invention is to provide a new highly reliable disk apparatus.
A third object of the present invention is to provide a new head suspension to prevent dust generated between a pivot and pivot contact surface.
A fourth object of the present invention is to provide a new head suspension which reduces sliding between the pivot and pivot contact surface.
In the present invention, an intermediate member having a hardness different from that of a pivot is provided on at least one of the pivot and the surface opposed to the pivot. According to this structure, the pivot is in contact with the intermediate member. Since the intermediate member is not as hard as the pivot, the pivot rubs the intermediate member to control the sliding of the pivot. Therefore, these elements can bear the acceleration of a head suspension in high speed operation. Moreover, generation of dust can be better controlled and reliability can also be improved.
Intermediate members may be provided on both the pivot and the surface opposed to the pivot. However, one intermediate member has hardness higher than that of the pivot and the other member has hardness smaller than that of the pivot. According to this structure, the intermediate members are in contact with each other. Since there is a large difference of hardness between these members, their friction coefficient becomes large. Therefore, the pivot can bear a larger acceleration.
Moreover, in the present invention, a recess can be formed at the contact surface between the gimbal or load beam and the pivot. According to this structure, a part of the pivot enters the recess and thereby movement of the pivot is restricted within the range surrounded by the recess. Therefore, sliding of the pivot is restricted to enable high speed movement of the head suspension. Here, it is also possible that the intermediate member consisting of the material having the hardness which is smaller than that of the pivot is arranged at the surface to be in contact with the pivot. According to this structure, not only the moving range of the pivot is limited but also wear of the pivot is further alleviated. Particularly, when the intermediate member is the layer covering the signal line for transmitting the signal to the head, the existing element may also be used as the intermediate member, which is preferable from the viewpoint of cost.
Moreover, in the present invention, projections may be formed along the longitudinal direction at the contact surface with the pivot of the gimbal or load beam. A surface of each projection is formed vertical to the moving direction of the load beam. According to this structure, movement of the pivot toward the radial direction of the disk may be restricted because the projections work as walls. Therefore, sliding of the pivot in the radial direction of the disk is restricted, to assure high speed movement of the head suspension.